﻿function lazyload(option) {
    var settings = {
        defObj: null,
        defHeight: 0
    };
    settings = $.extend(settings, option || {});
    var defHeight = settings.defHeight, defObj = (typeof settings.defObj == "object") ? settings.defObj.find("img") : $(settings.defObj).find("img");
    var pageTop = function () {
        return document.documentElement.clientHeight + Math.max(document.documentElement.scrollTop, document.body.scrollTop) - settings.defHeight;
    };
    var imgLoad = function () {
        defObj.each(function () {
            if ($(this).offset().top <= pageTop()) {
                var src2 = $(this).attr("src2");
                if (src2) {
                    $(this).attr("src", src2).removeAttr("src2");
                }
            }
        });
    };
    imgLoad();

    // 绑定滚动事件 
    $(window).bind("scroll", function () {
        imgLoad();
    });
}